help by `?`?

[kohske]

Is there way to show help page in the package that is loaded via load_all?

e.g.,

> l(ggplot2)
Loading ggplot2
> ?aes
No documentation for ‘aes’ in specified packages and libraries:
you could try ‘??aes’

[hadley]

No - and I don't see an easy way to do this. You can use show_rd to see the documentation for a file in a source package though.

[kohske]

Yes, but show_rd is file-name based, while ? is object-name based.
Ok, maybe I will hack ? in future.

[hadley]

It's moderately difficult because you need to build up an index from topic to Rd file by looking at all the Rd files.

[kohske]

Yes, but Rd file is well structured so it might not be so difficult.

At the moment, reverse lookup of Rd from function (or object name) is sufficient,
so grep alias *.Rd might be the first step.

[kohske]

Of course, tools:::parse_Rd is better.

[kohske]

I mean like this:

# when load_all(...)
# it makes index of the package inside `namespace:devtools`
files <- list()
files[["ggplot2"]] <- dir("~/Dropbox/dev/R/ggplot2/man", "\\.Rd$", full = TRUE)

r <- lapply(files[["ggplot2"]], function(x) {
  r <- tools:::parse_Rd(x)
  unlist(r[which(tools:::RdTags(r) == "\\alias")])
})

aliases <- list()
aliases[["ggplot2"]] <- r

# and accessor
devq <- function(p, f) {
  i <- which(sapply(aliases[[p]], function(a) any(f == a)))
  print(files[[p]][i])
  if (length(i) == 1) show_rd(p, basename(files[[p]][i]))
}

# use it
devq("ggplot2", "aes")

[hadley]

Hmmm, the problem is then keeping the index in sync after you roxygenise - although I guess document could also update it. And I think we'd just modify show_rd so it could either accept the name of a topic or a file name.

[kohske]

Hmmm, the problem is then keeping the index in sync after you roxygenise - although I guess document could also update it.

indexing takes place every time when load_alled the package, so I think there is no sync problem.

But,

And I think we'd just modify show_rd so it could either accept the name of a topic or a file name.

Agreed. This is more simple. Perhaps looking up the topic is not so heavy, so we don't need index.

[wch]

With the #126 pull request, this is closer to working.

In help(), this is how it tries to find the help file:

 paths <- index.search(topic, find.package(package, lib.loc, verbose = verbose))

With the changes in the pull request, find.package now finds the directory of the working version of the package, rather than the installed version. I think it uses the path attribute of the <package:ggplot2> environment.

find.package('ggplot2')
# "/Users/winston/Projects/ggplot2"

# with old version of devtools, this reported:
# "/Users/winston/R-dev/ggplot2"

But utils:::index.search looks for help/aliases.rds or help/AnIndex, and these files don't exist. So the index still has to be created somehow.

[hadley]

Hmmm, I could probably figure out how to create those files with roxygen, and then people would have to put them in .gitignore or similar.

[wch]

I think you'd also have to generate the help/ and html/ directories.

Another possible solution is to define a function like dhelp(), which would search the man/ directories of all packages loaded via devtools, and then run show_rd for the requested page. Or maybe it's possible to redefine ? to search devtools-loaded packages, and then if it doesn't find the help page, to call the regular ? function.

[hadley]

I think this will be called dev_help or maybe devhelp